1. Field of the Invention
This invention relates to a method of and an apparatus for reproducing color for use by an output device such as a printer outputting an output image according to color image data. More particularly, this invention relates to a technology of reducing a colorimetric bungle between the output image outputted from the output device and the color image data inputted from a color image scanner. In other words, the technology is to match the output image of the output device with the color image data of the color image scanner.
2. Description of the Related Art
Recently, according to demands of high quality of an image for a color image medium such as TV (television), an output image from an output device corresponding to color image data, such as a printout, i.e., hard copy, of a color image from a printer, is strongly required to be higher quality. To accomplish the higher quality of the printout by the printer, it is necessary to match an output image with original color image data. The output image is, for example, a print image printed out from the printer corresponding to the color image data. The original color data are, for example, the color image data inputted from a color image scanner.
For matching color as mentioned above, a conventional printer takes a method for reproducing color as follows.
When reproducing color, the color image data to be outputted, for example, color space data supplied from a data base are processed by a predetermined color converting procedure. This color converting procedure has a compressing saturation procedure to compress a saturation into the color space data. The compressing saturation procedure produces output image data comprising a plurality of color information including cyan, magenta, and yellow to be suitable for printing by the printer. The output image data are supplied to the printer.
The compressing saturation procedure is a procedure for compressing the saturation of the color image data into a gamut of the saturation corresponding to each hue wherein the gamut of the saturation is capable of reproducing color (color representation) by the printer. That is, the compressing saturation procedure is a procedure for compressing the saturation into a reproducing saturation range. FIG. 1 shows the compressing saturation procedure in a general idea.
On the compressing saturation procedure, saturation ranges of color light in the color image data and reproducing saturation ranges of the printer are calculated. The saturation ranges of the color and the reproducing saturation ranges of the printer are stored in a memory. A required compression rate is calculated from both of the saturation ranges corresponding to each hue. Then, the compressing saturation procedure is processed with the compression rate. The result of the compression is stored in a memory for use of the color image data. The color image is outputted based on the stored data in the memory to reproduce color.
However, the saturation reproducing ranges of the printer are different from each other corresponding to each hue. Therefore, as the conventional compressing saturation procedure as described above is processed, it is possible of breaking color balance of the output image.
The saturation reproducing ranges of the printer are generally narrower than the saturation ranges of color light. In particular, the saturation reproducing ranges of the printer are remarkably narrower than the saturation ranges of color light in accordance with becoming higher lightness or lower lightness. Therefore, in the case of the color image data which have a wider range of the lightness, the image must have subdued colors lacking of vividness.